Expert: John Snyder - 3/13/2007

Question
We recently brewed a batch of beer and bottled 1/2 of it in regular 12 oz. metal capped bottles and 1/2 in 16oz flip top bottles.  All of the metal capped bottles were good but only 3 out of about 24 flip top were good - the rest were all flat.  Any idea what happened.  The bottles and caps were new.  

Answer
Based on the info,you submitted,I would surmise the problem was in the sealing of the flip top bottles(probably the rubber),allowing the CO2 to escape.In the event you use those bottles again,I would suggest submersing the top of the bottles in water,ever so often,to see if any bubbles are coming from the tops,indicating the escape of CO2